The present invention relates to a condenser for an air-conditioning system of a vehicle and comprises a block of tubes and ribs which is provided with collecting tubes on both sides, a tube-shaped collector being arranged in parallel to one collecting tube and forming a unit with this collecting tube.
A condenser of the above described type is shown in European Patent Document EP 0 480 330 A2.
An object of the present invention is to provide a condenser of the above-described type in which it is possible to monitor the operation of the air-conditioning system without the requirement of additional connections which harbor the risk of leakages.
This and other objects are achieved in that at least one float is arranged in the collector which carries a transmitter element to which a receiver element is assigned which is arranged on the outside on the collecting tube and receives signals of the transmitter element through a wall of the collector.
By means of the present invention, it is possible to obtain and analyze, during filling, a signal indicating the correct filling or, during operation, a signal indicating the minimum amount of refrigerant, without the requirement of a connection which penetrates into the refrigerant circulating system. By avoiding such an additional connection, the danger is eliminated that this connection may leak and result in a loss of refrigerant.
In certain embodiments of the invention, two floats are arranged in the collector, of which an upper float is assigned to a filling detector and a lower float is assigned to a detector which responds when there is a falling-below a minimal filling. When the air-conditioning system is being filled with refrigerant, for example, the filling detector will emit a signal to a filling apparatus which indicates the correct filling amount and terminates the filling operation. The detector responding to the minimal filling emits, for example, a signal to a display device on the dashboard of a vehicle so that the operator of the air-conditioning system is made aware of the fact that the air-conditioning system is in need of servicing.
In a further development of the invention, the lower and/or upper float is arranged in a calm-flow area of the collector. This ensures that refrigerant flows have no influence on the position of this float so that no erroneous signal emission has to be feared which is caused by different flow velocities of the refrigerant.
In an embodiment of the invention, it is provided that the at least one float is displaceable on a slideway. In another embodiment, it is provided that the at least one float is disposed to be swivellable about a swivel axis. This type of bearing of the float has the advantage that, particularly in the response area of the detector or detectors, even short paths of the float and therefore small changes of the liquid level result in clear differences in the respective emitted signals.
In another embodiment, the receiver element is mounted on a cover or on the bottom of the collector. In an advantageous development of this embodiment, it is provided that the cover and/or the bottom of the collector is provided with a tube-shaped projection which is closed on one side, which projects into the interior of the collector and in which a receiver element is arranged. Also in this embodiment, the receiver element is arranged on the outside on the collector. Also in this case, the receiver element receives signals through the wall of the collector, specifically through the cover or the bottom. In this embodiment, the receiver element is arranged in a well-protected manner inside the cover or the bottom. A securing with respect to a torsion insert is not required for the dryer. In an advantageous further development of this embodiment, the float is guided on the projection of the cover or of the bottom.
Certain embodiments of the invention provide that the at least one float is disposed on a housing of a dryer which can be inserted into the collector which is provided with an insertion opening that can be closed by a detachable cover. Advantageously, the condenser proper is a soldered construction whose soldering takes place at a high temperature in a furnace. By arranging the float or the floats on the housing of a dryer which can be inserted subsequently, it is avoided that the float and/or its transmitter element and/or its bearing or guide is subjected to the high soldering temperatures which may result in damage or disturbances.
In further embodiments of the invention, at least one float is provided with a permanent magnet which serves as the transmitter element and to which a Hall effect element or a Reed switch is assigned as the receiving element which is arranged on the exterior side of the collector. In both embodiments, the signal is clearly and reliably transmitted through the closed wall of the collector without the necessity of providing an opening or the like for this purpose.
In still further embodiments of the invention, the transmitter element and the receiver element are arranged such that a contact is closed when refrigerant is absent. This makes it possible to carry out a test after assembly, while the refrigerant has not yet been filled in, by which it is determined whether a float is installed which has a transmitter element and whether there is operatability.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.